The invention relates to a method and an arrangement for implementing transceiver operation in a radio system in for example third generation mobile systems.
The object of the third generation mobile system UMTS (Universal Mobile Telecommunication System) is successful integration of the different sub areas of telecommunication. The UMTS is based on the spread spectrum technology, which has previously been used in military applications. In the spread spectrum technology, several users are able to simultaneously use the same frequency band. The spread spectrum technology comprised by the UMTS is typically implemented by the WCDMA technology (Wideband Code Division Multiple Access). The potential data transmission capacity in the UMTS is significantly higher than for example in the GSM technology.
The base stations in a mobile system are usually sectored to enhance transceiver operation. In accordance with prior art, the transmitter functions of two sectors having different carriers are implemented with different transmitters. Each sector-specific transmitter comprises a transmitter unit, a power amplifier and a filter unit, and cables between these units. The drawbacks of said separate structures include high costs due to the amounts of components and different cables called for by the separate structures. The minimization of transmission losses requires large, and expensive, cables at the base station. Separate structures require relatively much space owing to the large size of the power amplifier, in particular. Radio systems based on the WCDMA technology require the use of expensive and complex linear amplifiers as power amplifiers in transmitter operation. The need for a separate linear amplifier for each transmitter is a significant drawback.
Receivers are typically also connected to said sector-specific transmitters, i.e. transceivers are involved. The reception operation of transceivers can be implemented by the use of diversity, i.e. two or more receivers receive simultaneously from the same sector. Diversity can be utilized for example by eliminating spurious signals from the desired signal by comparing the received signals. This means that said drawbacks associated with the transmitter block also exist in reception, which is further emphasized when diversity is used in the implementation of the reception. The transceiver of each sector requires a receiver amplifier and cabling, which further increases the costs.
It is thus the object of the invention to implement a method and an apparatus for implementing the method so as to solve the above problems. This is achieved by an arrangement for implementing transmitter operation at a base station, the arrangement comprising a power amplifier for amplifying signals to be transmitted. The power amplifier in the arrangement is a multifrequency amplifier, and the arrangement comprises in different sectors at least two transmitter units for generating signals at different frequencies, connected to the same multifrequency amplifier, a filter unit comprising transmitter filters for said signals to be transmitted, a separate cable for transmitting signals between the multifrequency amplifier and the filter unit, and in different sectors at least two antennas for transmitting signals to their sectors, and at least two antenna cables, each antenna being connected with its antenna cable to its transmitter filter in the filter unit.
The invention also relates to an arrangement for implementing transceiver operation at a base station, the arrangement comprising a power amplifier for amplifying signals to be transmitted, and a first receiver amplifier for amplifying received signals. The power amplifier in the arrangement is a multifrequency amplifier, and the arrangement further comprises in different sectors at least two transmitter units for generating signals at different frequencies, connected to the same multifrequency amplifier, a filter structure comprising as filters at least two different transmitter filters and at least two different receiver filters for filtering signals to be transmitted and received, in different sectors at least two antennas for transmitting and receiving signals, and at least two antenna cables, each antenna being connected with its antenna cable to at least one transmitter filter and to at least one receiver filter in the filter structure, a filter unit for filtering further the received signals, a first receiver amplifier connected to at least two sector-specific receiver amplifiers, and a separate cable for transmitting signals between the multifrequency amplifier and the filter unit, between the filter unit and the filter structure, and between the filter unit and the first receiver amplifier.
The invention also relates to an arrangement for implementing receiver diversity transceiver operation at a base station, the arrangement comprising a power amplifier for amplifying signals to be transmitted, and a first receiver amplifier for amplifying signals received. The power amplifier in the arrangement is a multifrequency amplifier, and the arrangement comprises in different sectors at least two transmitter units for generating signals at different frequencies, connected to the same multifrequency amplifier, a filter structure comprising as filters at least two different transmitter filters and at least two different receiver filters for filtering signals to be transmitted and received, at least two antennas and antenna cables in different sectors, each antenna being connected with its antenna cable to at least one transmitter filter and to at least one receiver filter in the filter structure, a filter unit for filtering further the received signals, a first receiver amplifier connected to at least two sector-specific receiver amplifiers, a separate cable for transmitting signals between the multifrequency amplifier and the filter unit, between the filter unit and the filter structure and between the filter unit and the first receiver amplifier, and at least one receiver branch in said sectors connected to said sector-specific receiver amplifiers.
The invention also relates to a method of implementing transmitter operation at a base station, in which method a power amplifier amplifies signals to be transmitted. Further in the method, at least two transmitter units in different sectors transmit signals at different frequencies to the same multifrequency amplifier acting as the power amplifier, the signals amplified by the multifrequency amplifier are transmitted by a separate cable to a filter unit and the filter unit filters the signals to sector-specific antennas.
The invention further relates to a method of implementing transceiver operation at a base station, in which method a power amplifier amplifies signals to be transmitted, and a first receiver amplifier amplifies signals received. Further in the method, at least two transmitter units in different sectors transmit signals at different frequencies to the same multifrequency amplifier acting as the power amplifier, the signals amplified by the multifrequency amplifier are transmitted by a separate cable from the multifrequency amplifier to a filter structure, the filter structure filters at least two signals to be transmitted at different frequencies, sector-specific antennas transmit the signals to be transmitted at different frequencies, and receive the signals to be received at different frequencies, the filter structure filters the at least two signals received at different frequencies, the received signals are further filtered with a filter unit and the filtered received signals are transmitted along a separate cable from the filter structure via the filter unit to the same first receiver amplifier that amplifies said signals, whereupon the signals received from the different sectors are transmitted to sector-specific receiver amplifiers.
The invention further relates to a method of implementing receiver diversity transceiver operation at a base station, in which method a power amplifier amplifies signals to be transmitted, and a first receiver amplifier amplifies signals received. Further in the method, at least two transmitter units in different sectors transmit signals at different frequencies to the same multifrequency amplifier acting as the power amplifier, the signals amplified by the multifrequency amplifier are transmitted by a separate cable from the multifrequency amplifier to a filter structure, the filter structure filters at least two signals to be transmitted at different frequencies, sector-specific antennas transmit the signals to be transmitted at different frequencies, and receive the signals to be received at different frequencies, the filter structure filters the at least two signals received at different frequencies, the received signals are further filtered with a filter unit, the filtered received signals are transmitted along a separate cable from the filter structure via the filter unit to the same first receiver amplifier that amplifies said signals, whereupon the signals received from the different sectors are transmitted to sector-specific receiver amplifiers, and signals are received from said sectors at least at one receiver branch, from which the received signals are transmitted to said sector-specific receiver amplifiers.
The preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on the idea that at least two transmitter units in different sectors transmit signals at different frequencies to the same multifrequency amplifier that acts as a power amplifier and amplifies said signals. After the amplification, the signals are transmitted along separate cables to a filter unit in which sector-specific transmitter filters filter the amplified signals apart into antenna branches of their sectors, in which branches the signals are transferred along a sector-specific antenna cable to a sector-specific antenna.
The invention is also based on filtering signals that are at different frequencies and are transmitted to a multifrequency amplifier by transmitter units of at least two different sectors and amplified by the multifrequency amplifier with sector-specific transmitter filters in a filter structure, wherein signals received from said sectors at different frequencies are also filtered in sector-specific receiver filters. After said filtration, the received signals are transmitted along a separate cable via a filter unit to a first receiver amplifier, from which each signal is applied to a sector-specific receiver amplifier.
The method and arrangement of the invention provide significant advantages. Implementing transmitter operation or transceiver operation according to the invention brings about major financial savings, since only one power amplifier, in the invention a multifrequency amplifier, is needed for at least two transmitter units in a transmitter. This typically also means that only one power amplifier is needed for at least two sectors. Particularly in radio systems based on the WCDMA technology, in which linear amplifiers have to be used as power amplifiers, reducing number of linear amplifiers by at least a half leads to considerable financial savings. In the same way, this also brings about important savings in space, since linear amplifiers, in particular, are bulky. A further advantage of the invention is that is allows common separate cablings to be used for signals transmitted by both transmitter units and, similarly, for signals received in reception. The need for fewer cables also means considerable savings, since the cables used for said purpose in a base station are extremely expensive. Furthermore, as regards a transceiver, a reduction in the number of first receiver amplifiers leads to savings both in costs and space, which increases in importance when the receiver operation is implemented by the use of diversity.